Time course studies of events that may be associated with the activation of alveolar macrophages will be conducted. Glucose oxidation through the hexose monophosphate shunt and the content as well as the release of some lysosomal enzymes will be measured using alveolar macrophages incubated with agents shown to enhance macrophage cytotoxicity. Bacterial endotoxin and the lymphokine, macrophage migration inhibitory factor (MIF), will be tested using alveolar macrophages from normal rabbits and animals immunized with live Bacillus Calmette-Guerin (BCG) cells that induce a granuloma response in the lung. Hexose monophosphate shunt activity will be quantitated by measuring the 14CO2 produced from (1-14C)-glucose. Lysozyme, acid phosphatase and beta-glucuronidase will be measured in the lysosomal enzyme studies. Lymphocyte culture supernatants and sera containing MIF activity have been generated in vitro and in vivo using periodate treated lymphocytes and BCG immunized animals, respectively. These lymphokine preparations will be fractionated using Sephadex column chromatography and studied for ability to enhance macrophage cytotoxicity and proliferation. A time course study of cyclic GMP and cyclic AMP levels will be done with alveolar macrophages during their incubation with lymphokine fractions shown to enhance macrophage cytotoxicity or increase macrophage cell proliferation. The objectivity of these experiments is to provide an accurate assessment of the temporal relationship of any changes noted in particular macrophage functions and cyclic nucleotide levels. Results from such studies should help to elucidate the role of cyclic AMP and cyclic GMP as potential intracellular modulators of macrophage function.